Liquid circulating apparatus



Feb. 1, 1949. w. KURZ LIQUID CIRCULATING APPARATUS Filed Aug. 24, 1921.5

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Patented Feb. l, 1949 UNITED STATT-:s PATIENTV OFFICE I LIQUTD ciciiizi; APPARA'rUs l William Chicago, Ill., assignor to Precision Scientific Co.,` Chicago, Ill., a corporation of Illinois l Application August`2fl, 1945, Serial No. 612,471 `1 claim.` (c1. 259-96) This invention relatesto constant temperature liquid circulating apparatus.

Apparatus of the character here involved is useful for controlling and maintaining constant temperatures in refractometers, polarimeters, viscosimeters, incubators, calorimeters, etc., where close temperature control is essential. c In refractometers, for example, variation of one degree C. in temperature will result in a change of plus or minus .0005 in the refractive index` of a liquid. The successful use of such apparatus therefore requires the maintenance of aconstant temperature. l l

One of the objects of the invention a simple and inexpensive apparatus by which temperature controlling liquid is efficiently circulated during temperature conditioning so that its temperature throughout will be constant.

Another object of the invention is to provide mixing and circulating means of such eiciency that a relatively small volume of heat exchanging liquid (permitting the use of a small sized apparatus) may be maintainedat a degree of temperature constancy which has heretofore characterized only apparatus of very large size and capacity.

A further object of the invention is to provide a pump accessory which Will serve both as a supply pump booster and as an aid in circulating and mixing the'liquid with reference to the temperature regulating devices.

Other objects and advantages of the invention will become apparent from the following description of one apparatus embodying the invention and illustrated in the accompanying drawing.

In said drawing:

Fig. 1 is a perspective View of the mixing and circulating devices removed from the surrounding apparatus; and

Fig. 2 is a fragmentary sectional elevation on a larger scale and taken on plane 2-2 of Fig. 1, of the lower portions of the circulating and mixing devices and the enclosing liquid reservoir.

In the illustrative apparatus the heat exchanging liquid (e. g. water) is contained in a tempering vessel I which is advantageously jacketed and provided with temperature regulating means (not shown) for supplying heat to or removing it from (i. e. cooling) the liquid. Such means include devices for supplying and removing heat and an adjustable regulating thermostat, details of both of which form no part of the invention. Any appropriate temperature regulating devices may be used.

The overall ellciency of the apparatus depends is to provide not alone on the efficiency of the thermostatic regulator but also on the uniformity with which the temperature of all portions of the liquid is maintained. This in turn depends on the'univ formity and efficiency with which all portions of the liquid are exposed to the temperature Convection currents cannot regulating means. e v be depended upon, particularly in small apparatus, to maintain constant liquid temperature.`

The liquid is therefore mechanically circulated and mixed or agitated to insure uniform comregulating surfaces.

The illustrative mixing and circulating devices l y II and I2 are here shown mounted on a common vertical shaft I3 which may advantageously be directly coupled to the shaft of driving motor I4. The latter is mounted on posts I5 projecting upwardly from the top I6 of pump housing I1. Two of such posts, I8 and I9, may advantageously serve as pump delivery and return pipes. Posts I5 extend above and below cover ZI which rests on and covers vessel IU, thereby serving as the supporting base for both motor and pump housing. Pipes I8 and I9 are provided-with the fittings 22 by which terminal nipples 23 may be connected to the pipes. The upper T openings are plugged by post elements 24 which. extend to and aid in supporting the motor. Hose or other flexible lines may be slipped over nipples 23 to connect the circulating pump with the device to be supplied with heat exchanging liquid. Return vpipe I9 discharges through an appropriate orifice 21 at a point above Vthe pump housing and remote from the pump mixing of return liquid with and tempering by that in the reservoir. Such mixing as may occur, however, is not solely relied upon to elfect uniform mixing of the liquid. This is effected by the mechanical agitator II in the form of a double bladed impeller connected with the lower end of shaft I3 and rotating in such direction as to drive the liquid upwardly. The upwardly driven liquid encounters a curved deecting surface 28 on the exterior of the pump housing II thus` setting up elongated circulating paths represented by arrows 29 Which effect not only a thorough mixing of the liquid to secure uniform temperature throughout but to carry the liquid uniformly into contact with the walls of vessel I0 or other surfaces through which heat is exchanged to regulate the liquid temperature, either by heating or cooling to the proper level.

A fraction of the liquid driven upwardly b the mixing impeller II enters the pump casing through axial opening 3I'therein around shaft I3, and enters centrifugal impeller 32, also on shaft I3, by which the liquid is circulated as afore- 5 said. The liquid discharged fromr impeller 32 travels upwardly through pipe I8 and returns Y 4 used to advantage in different combinations and l sub-combinations.

I claim as my invention: A constant temperature liquid circulating ap- 5 paratus comprising in combination a storage vesthrough pipe'l 9 las above' described: The mixingiii device II therefore serves Aadditionallyasa booster for the centrifugal impeller 32 and particularly avoids any short circuiting (and faulty tempersel, -a cover therefor carrying a driving motor having a shaft extending through said cover into said vesselandwarrying at sitsloWer end :adjacent the vbottom of said vessel a mixing agitator adapt- 10 ed to create circulating currents of liquid, a pump ing) of the liquid such as might occur if supply to impeller 32 depended upon the suction created therefore withdraw inadequately tempered or non-uniformly mixed liquidi The agitatortll de-"z livers only thoroughly mixed liquid and only a thereby. Such suction'woulddtendftodraWtliquid-f through the paths of least resistancefandmi'ght'i-l fraction of thatcirculated by the mixing idevice (the balance being repeatedly circulated), therecasing in said vessel, a plurality of posts from saidvv cover and supporting said pump casing-said posts extending4 upwardly above said casing to support-.,saidx motor, apair of said posts being hollow and* constituting liquid discharge and return conduits forsaid pump casing, an impeller carried bylsaid shaft inside said casing, said casing having an opening therein for Withdrawingfal portion of the circulated liquid from said vessel, said return conduit having a discharge byinsuring deliveryto the centrifugal'pumpbfi uniformlyk tempered liquid.

Pump casing I1 is here shown connected'to thef- J pump A,cover I6 bylscrewspassing throughfflangesvf 34 in t the housing. Pump cover I 6 carries-the". bearing -35 for. shaft I3. `The supporting #posts I5! areconnected.to-pump cover I6 ibyscrewsw threaded into the ends of theposts or-inlcase ofthepipe-l which. serves as a discharge lconduitiorthe pump',rby av base 'ange 31.

Obviously Zthe invention is not limitedto'fthef'- detailsgof the illustrative apparatus sincerthes'e`AA may ,be variously modified.v Moreover it is not indispensable that all features ofthe inventionfbe i usedyconjointlycsince various features fmay-s-be openingalra point'remote from said agitator;

WILLIAM KURZ;

REFERENCES CITED ff The following-'references are'of recordin the file "of thispatent:

y 'UNITEDs'rATEsPATEN-rrs Number--` 

